The traditional view of the Roman incursion into Scotland was that Gnaeus Julius Agricola, who became governor of Britain in the late summer of 77AD, pushed north after a campaign in Wales. The main source for the information is the Roman writer Tacitus. But Tacitus was the son-in-law of Agricola and some historians believe that he increased the significance of the role of his father-in-law.

Again, tradition says that Agricola was the first Roman to push beyond present-day Perth and build a series of wooden forts and watch-towers, known as the Gask Ridge, around 80AD. But recent research has established that the forts were built ten years earlier than this, during the governorship of Petilius Cerealis. It would appear that Agricola was responsible for some of the reconstruction of these fortifications. It is thought that the forts had been constructed to protect the Romans' new-found trading partners and farmers from incursions from the Caledonii, further north - "the most distant inhabitants on earth" according to Tacitus.

Galgacus or Calgacus was a chief of the northern native tribe named Caledonii by the Roman invaders. Galgacus is thus the first Scot to be named in written history. He initially fought a determined resistance to the Romans in a series of skirmishes as the Roman legions, led by Agricola, marched up the east coast of Scotland, reaching as far as present-day Moray as far as the river Spey, and possibly even further

The Caledonii continued to attack the extended Roman supply and communication lines and the Romans only managed to beat them off with difficulty (according to Tacitus). But in the late summer of 83AD (some sources give 85AD), the Romans heard about a gathering of an estimated 30,000 Caledonii on a hill named by Tacitus as Mons Graupius (a name which was later eroneously transcribed in the 1470s as Mons Grampius, giving rise to the modern Grampian mountains - rather than Graupius mountains - to describe the eastern flank of the central Highlands). The precise location of the battle is unknown but may have been Bennachie near Inverurie in Aberdeenshire.

Agricola advanced quickly to confront the assembled Caledonii in a pitched battle - the first and only one recorded. The Caledonii war chariots were useless on the uneven ground and the Romans successfully beat off their initial attacks. The Romans later unleashed 2,000 cavalry and cut the Caledonii to pieces. Tacitus claims that Roman casualties were 360 and the Caledonii lost 10,000.

In the course of his narrative, Tacitus puts into the mouth of Galgacus a rejection of pax Romana with the well-known words, spoken before the battle: "they make a solitude and call it peace".